Revert "Better handling of trying to configure already instantiated component"

This reverts commit 6b15768a3f.

framework/yii/base/Module.php

@@ -546,16 +546,11 @@ abstract class Module extends Component
 	public function setComponents($components)
 	{
 		foreach ($components as $id => $component) {
-			if (isset($this->_components[$id]) && !($this->_components[$id] instanceof Object)) {
 			if (isset($this->_components[$id]['class']) && !isset($component['class'])) {
 				$component['class'] = $this->_components[$id]['class'];
 			}
 			$this->_components[$id] = $component;
 		}
-			else {
-				throw new Exception('Cannot set component "'.$id.'" that is already instantiated.');
-			}
-		}
 	}
 
 	/**